The document discusses cement, including its history and manufacturing process. It begins by explaining that the Romans originally used the term "cement" and describes how modern cement is made. The key points are: 1) Cement is made by burning a raw mixture of limestone and clay in a kiln at high temperatures, forming clinker which is then ground into a powder. 2) The main minerals formed are tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite which give cement its strength. 3) The manufacturing process involves quarrying limestone, preprocessing raw materials, firing the mixture at 1450°C,

1. CEMENT
The name "cement" goes back to the Romans who used the term
"opus caementitium" to describe masonry which resembled concrete
and was made from crushed rock with burnt lime as binder. The
volcanic ash and pulverized brick additives which were added to the
burnt lime to obtain a hydraulic binder were later referred to as
cementum, cimentum, cäment and cement. Cements used in
construction are characterized as hydraulic or non-hydraulic.

2. Examples of concrete constructions

3. Viaduct de Millau,
France
reinforced concrete
steel

4. The Øresund bridge
Large Infrastructure Great Belt,
Denmark

5. History of Portland Cement
In 1824, Joseph Aspdin, a British stone mason, obtained a patent for a
cement.
He heated a mixture of finely ground limestone and clay in stove and
ground the mixture into a powder.
He created a hydraulic cement - that hardens with the addition of water.
Aspdin named the product portland cement because it resembled a stone on the
Isle of Portland, British Coast.
With this invention, Aspdin laid the foundation for today's portland cement industry.

6. CEMENT
Definition – part cited from European standard EN 197-1:
„Cement is a hydraulic binder, i.e. a finely ground inorganic material
which, when mixed with water, forms a paste which sets and
hardens by means of hydration reactions and processes and which,
after hardening, retains its strength and stability even under water.“
„Cement conforming to EN 197-1, termed CEM cement, shall, when
appropriately batched and mixed with aggregate and water, be
capable of producing concrete or mortar which retains its workability
for sufficient time and shall after defined periods attain specified
strength levels and also possess long-term volume stability.“

7. CEMENT (Portland cement and blended cements)
• is finely ground inorganic material
• is hydraulic binder. It sets and hardens by reacting
chemically with water and is able to harden under water.
Setting and hardening is due to hydration reactions of
compounds of cement (mainly calcium silicates, also
calcium aluminates and -alumino ferites) with water.
This is called hydraulic hardening.
• hardened cement paste (cement + water) is stable in water.
• cement paste acts as adhesive when is mixed with sand and
aggregate (gravel,crushed rocks). Hardened cement paste
- binds the particles of sand - CEMENT MORTAR
- binds fine and coarse agregate - CONCRETE
Prepared cement concrete or mortar after mixing shall be
workable for sufficient time.

8. COMMON CEMENTS
Covered by European standard (STN) EN 197-1
EN 197-1 covers five main types of cement:
• CEM I Portland cement
• CEM II Portland-composite cement
Blended
• CEM III Blastfurnace cement cements
• CEM IV Puzzolanic cement
• CEM V Composite cement

9. PORTLAND CEMENT

10. PORTLAND CEMENT
- is finely ground hydraulic binder
It is produced by pulverizing clinker with calcium sulfate and
eventually other compounds.
Main constituent:
Portland cement clinker - is composed primarily of
- calcium silicates
- calcium aluminates and
- calcium alumino-ferites
Set controlling admixture: controls setting of cement
Calcium sulfate - usually gypsum (CaSO4.2H2O), or
(3-5 %) - hemihydrate (CaSO4.1/2H2O), or
- anhydrite (CaSO4), or
acts as set retarder - mixture of them

11. MANUFACTURE OF PORTLAND CEMENT
RAW MATERIALS
BURNING OF PORTLAND CLINKER
CHEMICAL AND MINERALOGICAL COMPOSITION OF
CLINKER
GRINDING OF CEMENT

12. MANUFACTURE OF PORTLAND CEMENT
SCHEME OF DRY PROCESS
Mining (quarrying) of raw materials
Limestone Argilaceous materials Iron ore
Clay, shale, marl corrections
grinding, blending, correctioning of composition
of raw materials
burning (sintering) a raw mixture up to 1450oC
into clinker - in cement kilns (mainly rotary kilns)
cooling of clinker - in a cooler
grinding of clinker with gypsum into cement
quality control of cement, packing and expedition

13. F.PEŤKO, T.VINICKÝ , J. PETLUŠ
quarry
Limestone Manufacture of cement
According: Holcim Rohožník
crusher
conveyer
Clay-pit:
mining of clay
Burning of clinker
Preheater (or precalciner) tower
1450 oC
homogenization cooler
and storage Rotary kiln
grinding mill

14. Grinding of clinker with gypsum and/or other materials to cement
finely ground material
Clinker from the kiln
cement
silos
Clinker silo (clinker storage)
rotary ball mill
grinding of cement
expedition

15. RAW MATERIALS FOR PRODUCTION OF CLINKER
MAIN RAW MATERIALS ADDITIONAL
(corrections)
marl
SiO2 -quartz sand
limestone clay, shale....
Fe2O3 – iron ore
Al2O3.2SiO2.2H2O
CaCO3 (MgCO3) Al2O3 - bauxite
e.g. kaolinite
CaO (MgO) SiO2, Al2O3, Fe2O3
Hydraulic oxides
RAW MIXTURE MIXTURE must have suitable chemical composition
Evaluated by HM = CaO
hydraulic modulus SiO 2 + Al 2 O 3 + Fe 2 O 3 HM = 1,9 - 2,4
Generally, raw materials consist of combinations of limestone, shale, clay,
sand, or iron ore. Most are mined from a quarry near the plant

16. COMPOSITION OF MIX OF RAW MATERIALS
To evaluate suitable composition of raw materials mixture (clinker)
- the values of following modules (parameters) are used
(chemical formulae represent weight percentages):
hydraulic modulus: CaO
HM =
HM = 1,9 - 2,4 SiO 2 + Al 2 O 3 + Fe 2 O 3
silicate modulus SiO 2
SM =
SM = 1,7-3,5 Al2O 3 + Fe 2O 3
aluminate modulus Al2O 3
AM =
AM = 1,5 - 3,0 Fe 2O 3
Oxide composition in raw materials for clinker is usually about
CaO MgO SiO2 Al2O3 Fe2O3 Na2O + K2O SO3
62-67 0,5-4 18-24 3-8 1,5-4,5 0,4 - 1,2 1,3

17. Limestone quarry – fy. Cement Hranice, a.s.
http://geologie.vsb.cz/loziska/suroviny/anorganicka_pojiva.html

18. Transport of limestone from a quarry

19. • limestone
• clay, shale
HOMOGENIZATION OF RAW MATERIALS

20. Correction of composition
of raw mix

21. MANUFACTURE OF PORTLAND CEMENT
RAW MATERIALS
BURNING OF PORTLAND CLINKER
CHEMICAL AND MINERALOGICAL COMPOSITION OF
CLINKER
GRINDING OF CEMENT

22. F.PEŤKO, T.VINICKÝ , J. PETLUŠ
Burning of raw mixture in cement kilns
into Portland clinker
Cyclones use
waste heat (air)
Rawmix is fed from the kiln
into preheater
Preheater (or precalciner) tower
1450 oC
homogenization
and storage
Clinkering zone
grinding cooler
mill Rotary kiln
Output of
Fig. According: Holcim Rohožník clinker

23. BURNING OF PORTLAND CLINKER
CLINKER is made by burning of raw mixture in
cement kilns
FUELS: pulverised coal, petroleum coke, waste oil, natural gas, spent tyres,
Burning temperature Shaft kilns
Rotary kilns
Max. 1450 °C
Steel tube - refractory lined
Slope: 1 - 4°
Length: 40 - 200 m
Diameter: 3 - 7 m
Rotation: about 1 revolution /
min
Rawmix is fed at the upper end
and slowly moves downhill toward
burner (counterflow movement)
Process: dry (wet is not used today)

24. Fuel used in
cement
production
Coal
Used tyres Other solid fuels
Czech republic

25. MANUFACTURE OF PORTLAND CEMENT
RAW MATERIALS COMPOSITION
FIRING OF PORTLAND CLINKER
CHEMICAL AND MINERALOGICAL COMPOSITION OF
CLINKER
Portland
clinker

26. PROCESSES DURING BURNING OF CLINKER
• Decomposition of some raw materials
(limestone, kaoline clay) in the preheater or the kiln ≤ 800 °C
CaCO3 → CaO + CO2
Al2O3.2SiO2.2H2O → Al2O3.2SiO2 + 2H2O
• High-temperature reactions taking place in the kiln ≤ 1450 °C
about 25 percent of the raw material mixture melts (partial fussion)
CaO SiO2 Al2O3 Fe2O3
Burning changes raw mix into cement clinker. Produkts
of reactions that compose Portland clinker are
Minerals (compounds): Calcium silicates,
calcium aluminates, and – alumino ferites

27. High-temperature reactions at clinker burning
3CaO.SiO2
(CaCO3)
SiO2 + Al2O3 + Fe2O3 2CaO.SiO2
CaO
3CaO.Al2O3
4CaO. Al2O3.Fe2O3
CaCO3 → CaO + CO2 900 °C
3CaO + Al2O3 → 3CaO. Al2O3
4CaO + Al2O3 + Fe2O3 → 4CaO. Al2O3. Fe2O3
2CaO + SiO2 → 2CaO.SiO2 ≤ 1200 °C
2CaO.SiO2 + CaO → 3CaO.SiO2 1200 - 1450 °C

28. PROCESSES AND REACTIONS DURING BURNING OF CLINKER
Informative scheme
• 100-200°C - evaporation of physical water
• 200-600 °C – releasing of water from clay minerals (dehydroxylation)
• 600-800 °C – decomposition of MgCO3, formation of CA, C2F (C2S)
• 800-900 °C – decomposition of CaCO3 (free CaO)
• 900-1100 °C - formation and decomposition of C2AS,
- begining of formation of C3A and C4AF,
- maximum content of free CaO (unbound)
•1100-1200 °C - most of C3A and C4AF is formed,
- maximum content of C2S CaO + 2SiO2→ 2CaO.SiO2
• 1260 °C - occurs first partial fussion (melted material)
• 1200-1450 °C - C3S forms 2CaO.SiO2 + CaO → 3CaO.SiO2
and content of free CaO therefore decreases

29. COMPARRISON: HYDRAULIC LIME - PORTLAND CEMENT
burning 1250 °C
Impure limestone, limestone-marl Hydraulic lime (natural
Calcite Clay minerals hydraulic lime)
CaCO3 + SiO2 + Al2O3 + Fe2O3 - CaO (free, quicklime)
- calcium silicates (C2S)
HYDRAULIC OXIDES - calcium aluminates
CaO CO2 - calcium alumino-ferites
Marl, limestone-marl burning 1450 °C
Limestone + clay, shale Portland clinker
Calcite clay minerals
almost any free CaO
CaCO3 + SiO2 + Al2O3 + Fe2O3
- calcium silicates (C2S, C3S)
HYDRAULIC OXIDES - calcium aluminates (C3A)
CaO CO2 - calcium alumino-ferites

30. Burner
Clinker
leaving
s) r
ial ke
the kiln
ter clin
ma of
w nt
(ra me
ve
Mo
Rotary kiln BURNING OF CLINKER

31. Edison – patent 1905

32. COOLING OF CLINKER
Clinker is discharged red-hot from the lower end of the kiln and
transferred to coolers to lower the clinker temperature
Portland cement clinker

33. MANUFACTURE OF PORTLAND CEMENT
RAW MATERIALS
FIRING OF PORTLAND CLINKER
CHEMICAL AND MINERALOGICAL
COMPOSITION OF CLINKER

34. MAIN MINERALS IN PORTLAND CLINKER
tricalcium silicate 3CaO.SiO2 (C3S) ALITE
dicalcium silicate 2CaO.SiO2 (C2S) BELITE
tricalcium aluminate 3CaO.Al2O3 (C3A)
tetracalcium aluminoferite 4CaO.Al2O3.Fe2O3 (C4AF) CELITE
Optical microscope image
of clinker minerals
(polished sections)
Brown crystals - alite
blue crystals - belite
bright interstitial material - ferrite
small dark inclusions of aluminate
http://www.understanding-cement.com/clinker.html

35. Conventional cement chemist notation
Is used to simplify the formulas are used mainly in chemistry of
cement. It is used for „short hand“ way of writing the chemical
formula of some oxides and water.
List of the abbreviations used:
Actual Abbr. Actual Abbr. Actual Abbr.
Formula Formula Formula
CaO C MgO M H 2O H
SiO2 S K2O K CO2
Al2O3 A Na2O A SO3
Fe2O3 F TiO2 T - -
Examples: • 2CaO.SiO2 ≡ C2S;
• Ca(OH)2 ≡ CH • 3CaO.Al2O3.13H2O ≡ C3AH13

36. MAIN MINERALS IN PORTLAND CLINKER
Main products of high-temperature reactions in the kiln
tricalcium silicate 3CaO.SiO2 (C3S) ALITE
dicalcium silicate 2CaO.SiO2 (C2S) BELITE
tricalcium aluminate 3CaO.Al2O3 (C3A)
tetracalcium aluminoferite 4CaO.Al2O3.Fe2O3 (C4AF) CELITE
2CaO(Al2O3,Fe2O3) C2(A,F)

37. CHEMICAL COMPOSITION OF PORTLAND CLINKER (%)
CaO MgO SiO2 Al2O3 Fe2O3 Na2O + K2O SO3
62-67 0.5-4 19-24 4-8 1.5-4.5 0.4 – 1.1 0,3 - 1
MINERALOGICAL COMPOSITION OF PORTLAND CLINKER (%)
3 CaO.SiO2 C3S 45 - 60 % Dominant
2 CaO.SiO2 C2S 15 - 30 % phases
3 CaO.Al2O3 C3A 3 - 15 %
4CaO.Al2O3.Fe2O3 C4AF 10 - 20 %
free lime < 1.5 (2) %
High content of unreacted oxides (CaO, MgO) can cause
expansion of cement (unsoundness) and affect setting time.
- result of insufficient burning and high content of lime in clinker

38. MANUFACTURE OF PORTLAND CEMENT
RAW MATERIALS
FIRING OF PORTLAND CLINKER
CHEMICAL AND MINERALOGICAL COMPOSITION OF
CLINKER
GRINDING OF CEMENT
Rotary ball mill
Clinker
+ Gypsum 2.5-5 %
Portland cement

39. GRINDING OF CEMENT
Steel balls in the mill
A 10 MW cement mill, producing cement at
Fired clinker
270 tonnes per hour. Wikipedia

40. GRINDING OF CEMENT AND DISPATCH
Clinker and 2,5-5 % of gypsum (or also other components) are finely
ground together in rotary ball mills to form final cement product.
- particles size of ground cement vary mostly from 1 - 200 μm (200 μm)
- blended cements contain, besides clinker and gypsum, also latent
hydraulic or pozzolanic constituents
- cement is stored in an bulk silo until needed by the customer
Fineness of ground cement is evaluated by its specific surface.
> 220 m2/kg according air permeability Blaine method
Fineness of cement affects almost all important properties of cement
Expedition /dispatch of cement
- in bulk - by trucks, rail, or barge
- in bugs - baged cement
www.gassmann-gmbh.com/frames.php?sprache=en

41. Dispatch of cement

42. Výrobcovia cementu na Slovensku
1 - HOLCIM, a.s. Rohožník
2 - CEMMAC, a.s. Horné Srnie
3 - Cementáreň Turňa, a.s. Turňa nad Bodvou
4 - Považská cementáreň, a.s. Ladce
5 - Stredoslovenská cementáreň Banská Bystrica, a.s.
6 - ZEOCEM, s.r.o. Bystré

43. SETTING AND HARDENING OF
PORTLAND CEMENT
(Cement mortars and concrete)
Reaction of cement with water
Hydration of clinker minerals
Release of heat
Setting and hardening
Structure development

44. SETTING AND HARDENING
OF PORTLAND CEMENT
Cement paste or slurry
- is obtained by mixing of cement and water
- consistency (fluidity) remains nearly constant for some time
- mixture can be cast (placed) into different shapes
Setting and hardening of cement paste
Is due to chemical reactions of cement with water
setting starts (initial set) 2 and 3 hours after mixing
setting develops until final set is obtained
hardening (strength gain) starts after final set
strength gain continues a long time with decreasing speed

45. definitions
Hydration of cement - the reaction of cement with water
Setting is stiffening of cement paste without significant
development of compressive strength.
It typically occurs within a few hours.
Hardening is significant development of compressive strength
It is normally a slower process
Lea: p.113
Exotermic chemical reaction accompanied by heat release
reaction
Hydration of cement is exotermic reaction
Consistency

46. Strength development during hardening of cement paste
Hydration of cement
Strength development
grains with different size
Compressive strength
[MPa]
Time [days]
Hydration of clinker minerals in cement paste is slow:
e.g. 3 μm after 7 days → strength increses gradually

47. Cement hydration
setting → hardening
Rate of heat evolution
Cement hardening
Contribution of Portland
cement minerals to
strength of cement
(after Bogue and Lerch)

48. Reaction of cement with water (hydration of cement)
≅ 23 %
Cement + water → main hydration products
clinker
C 3S Ca(OH)2 (portlandite)
C 2S 3CaO.2SiO2.3H2O (CSH-gel)
+ H2O
C3 A
C4AF 3CaO.Al2O3.3CaSO4.32H2O
3CaO.Al2O3.CaSO4.12H2O
gypsum
4CaO.Al2O3.13H2O
CaSO4.2H2O
(3CaO.Al2O3. 6H2O)
regulates the rate
of setting Calcium aluminate hydrates

49. Hydration of C3S a C3S
formation of hydrated reaction products
Idealized ratio of CaO : SiO2 : H2O
2(3CaO.SiO2) + 6H2O → 3CaO.2SiO2.3H2O + 3Ca(OH)2
2(2CaO.SiO2) + 4H2O → 3CaO.2SiO2.3H2O + Ca(OH)2
Calcium silica hydrates
Calcium hydroxide
CSH gel or (C-S-H phase)
imperfect crystals, gel structure relative large crystals
coloidal dimensions (1 - 500 nm) low strength
large surface area solubility 1.5 g/L
easily carbonatize
main contribution to strength
very low solubility (hydrolysis) Ca(OH)2 + CO2 → CaCO3 + H2O

50. Hydration of C3A (similarly also C4AF)
Main reaction products are:
- calcium aluminate hydrates (C4AH13 or C4AH19, C3AH6)
- complex calcium aluminate sulfate hydrates (ettringite, monosulfate)
1. Ettringite (trisulfate) forms by hydration of C3A in the presence of CaSO4
(e.g.gypsum). Reaction takes place at beginning of hydration of cement.
3CaO.Al2O3 + 3 CaSO4 + 32 H2O → 3CaO.Al2O3.3CaSO4.32H2O
2. After gypsum is consumed, C3A reacts with ettringite to form monosulfate:
2(3CaO.Al2O3) + 3CaO.Al2O3.3CaSO4.32H2O + 4 H2O →
→ 3(3CaO.Al2O3.CaSO4.12 H2O)
3. Later C3A reacts with water to form mostly tetra calcium aluminate hydrate
3CaO.Al2O3 + Ca(OH)2 + 18 H2O → 4CaO.Al2O3.19H2O
Ca(OH)2 is formed at hydration of calcium silicates

51. Characteristic of clinker minerals – during hydration
Tricalcium silicate, C3S: • hydrates rapidly
• strongly contributes to early and final strength of cement pastes
• has high heat of hydration: (670 kJ/kg)
Dicalcium silicate, C2S: • hydrates slowly
• strongly contributes to strength at later ages (> 1 week).
• increases chemical resistance of cement
• has low heat oh hydration: (350 kJ/kg)
Tricalcium Aluminate, C3A: • hydrates very rapidly;
• contributes slightly to early strength development.
• reduces chemical resistance of cement to sulfates (soils, waters)
(low percentage of C3A is required for sulfate resisting cement).
• large heat of hydration: (1060 kJ/kg), rapid during the first few days
Tetracalcium Aluminoferrite, C4AF: It contributes little to strength.
(iron and aluminum in raw mixture reduce the clinkering temperature
during clinker manufacture) and gives cement its gray color (Fe).
Low heat of hydration:

52. STRUCTURE AND COMPOSITION OF
HARDENED CEMENT PASTE
Hardened cement paste (HCP) is composed of:
• interlocked hydration products of cement
(portlandite, C-S-H gel, hydrated calcium aluminates and - alumino ferites)
• unhydrated residual cement grains
• pores of various dimensions (characterized by pore size distribution)
• gel pores in CSH gel < 3 nm
• capillary pores -space between hydrating grains 10 nm – 1 000 nm
• air pores or air voids > 50 μm up to about 2 mm.
Pore solution in hardened cement paste (HCP)
• Pores in HCP are partially filled with pore solution.
• Pore solution is saturated solution of Ca(OH)2
it contains also NaOH and KOH
• pH is about 13 -13,5 (from PC; lower from blended cements)

53. Soroka,
1979

54. Simplified scheme of hydrated cement paste microstructure
1. Unhydrated cement
2. C-S-H gel containing gel
pores (interlayer water)
Gel (or interlayer) pores have
size of 0.5-2.5 nm and occupy
about 28 vol. % of C-S-H gel
3. Capillary pores (capillary
water)
Capillary pores can have sizes
from 10 to 1000 nm (1 μm) and
even up to 5 μm. Volume and
size depends on water/cement 4. Hexagonal crystals of calcium
ratio and degree of hydration hydroxide (portlandite)

55. Hydrated cement paste microstructure
C-S-H
© 2010 Rouhollah Alizadeh, all rights reserved
Feldman-Sereda model for the The flaky C-S-H crystals
microstructure of C-S-H grown after 2 weeks of
Black lines: C-S-H sheet, Circles: hydration of C3S (W/C=0.8).
Adsorbed water, Crosses: Interlayer The stoichiometric C/S ratio of C-S-H
water and morphology of its crystals in
conventional cement systems depend
on the curing condition.
http://www.cementlab.com/cement-art.htm

56. Simplified scheme of hydrated cement paste microstructure
Capillary pore in hydrated
The transition zone (Ref 7)
cement paste (8)
7. Mehta, P.K. "Concrete Structures Properties and Materials", Prentice Hall, 1986
8. Feldman, F., and P.J. Sereda, Eng. J.. Vol 543, No. 8/9, 1970

57. Schematic representation of volumetric proportions in cement paste
before and during hydration
Microstructure
of cement paste

58. Influence of the water/cement ratio on the distribution of pore size in
hydrated cement paste

59. CHEMICAL COMPOSITION OF PORE SOLUTION
Portland K2O 50-70 %
cement Pore solution
Na2O 40-60 %
Solubility of Ca(OH)2 in the presence alkalies
Ions [mol/dm3]
0,03
[Ca ][OH ]
− 2
Na+ + K+ 0,2 - 1
Ca2+ (mol/l)
2+
Ks = γ3
±
0,02 OH- 0,2 - 1
Ca2+ ≅ 0,001
0,01
SO42- 0,02
0
pH 13,4 - 14
0 0,4 0,8 1,2
NaOH (mol/l)

60. Composition of pore solution is of prime importance for
chemical properties of cement composites. Although solubility
of Ca(OH)2 in water is about 0.02 mol.dm-3 at 20 °C and the pH
value of saturated solution is about pH 12.5; these parameters
are substantially affected by alkali metals. Alkali metals are
released from cement during its hydration. Because they do not
take part in the composition of the major cement hydration
products they accumulate in the pore solution forming Na+, K+
and OH− ions, respectively. Increase in OH− ion concentration
reduces significantly solubility of Ca(OH)2.
Pore solution in cement based composites therefore contains
relatively high concentration of Na+, K+ and OH- ions (up to 1
mol.dm-3), but concentration of Ca2+ and also SO42- is
considerably lower, for Ca2+ is often only about 1 mmol.dm-3.
The pH-value of the pore fluids in cement composites
(containing alkali metals) may well be greater than pH 12.5 in
the case of Portland cement the pH can prevail pH 13.5.

61. Thank you